1. Field of the Invention
The present invention relates to a fuel injection nozzle.
2. Description of Related Art
Conventionally, in a fuel injection nozzle 100 shown in FIGS. 6A, 6B, 6C, a nozzle hole group 102 is provided by disposing equal to or more than two single nozzle holes 101 close to each other, to improve diffusion of fuel that is injected. By arranging the single nozzle holes 101 close to each other to provide the nozzle hole group 102, sprays of fuel from the single nozzle holes 101 have an area in which they collide and interfere with each other, thereby increasing penetrating force of the sprays in an injecting direction and improving diffusion of fuel. However, in a direct fuel-injection engine such as a diesel engine, when fuel is injected through the nozzle hole group 102, an equivalent ratio tends to be uneven between an area in which sprays collide and interfere with each other and an area in which they do not collide or interfere, thereby often generating black smoke.
In addition, regarding a fuel injection valve that injects fuel into the direct fuel-injection engine, an outlet side of a nozzle hole is enlarged to prevent interference of the sprays of fuel with an intake and exhaust valves or an ignition plug, and to restrict attenuation of swirl force of a swirl flow (e.g., JP2001-214837A). However, according to the above-described art, it is presupposed that the spray is formed through a single nozzle hole, and description of sprays through a nozzle hole group is not given.